The invention relates to a microwave module and to a connection device therefor.
Microwave circuits are commonly used for various applications, and in particular in telecommunications.
These circuits can be used in particular for consumer applications and for space applications, and it is desirable to miniaturize them. To reduce the size of these circuits, use is made of integration technology whereby a set of circuits is associated in a plurality of layers thus forming an assembly which can be molded, for example.
Thus, a microwave circuit module is often in the form of a solid parallelepiped or cube.
As a general rule, such modules need to be connected together so as to transmit signals from one module to another or so as to interchange signals between modules.
For example, an active antenna comprises firstly a microwave module constituting a beam-forming network, and secondly radiating elements, each of which is associated with a microwave module. Thus, each module associated with a radiating element must be connected to the beam-forming module.
The various known connection techniques do not in general make it possible to comply with two important requirements, namely the ability to operate at any frequency (i.e. over a wide frequency band), and maximum compactness. The most usual solution for operation over a very wide band is to use coaxial connectors. However, such connectors occupy space within the module and outside the module that is difficult to make compatible with the desired miniaturization.
The module of the invention includes at least one connection device in the form of conductive zones, such as metallization zones, on an outer face, including a central zone and a peripheral zone, and inside the volume of the module, connection to said conductive zones is implemented by means of coplanar conductors comprising a central signal conductor and lateral ground conductors.
Thus, the invention combines xe2x80x9ccoplanarxe2x80x9d connection technology inside the microwave module with coaxial type technology on its outlet face. Since a coplanar line and the coaxial type conductive zones on the outlet face interconnect in continuous manner, there is no resulting disturbance in the electromagnetic field, so the passband is not reduced.
In a preferred embodiment, the coplanar lines inside the module are substantially perpendicular to the outlet face.
It should be observed that inside the module, beyond the access, i.e. beyond the connection with the conductive zones, the connections can be of any kind. In other words, propagation inside the module can rely on any type of microwave propagation technology, such as stripline, microstrip, waveguide, etc.. Naturally, it is also possible to use coplanar connections.
On the outlet face, the conductive zones can be constituted by three separate conductive zones, i.e. a central zone and two end zones in alignment with the central zone.
The peripheral zone can also be constituted by an annular zone forming a closed line.
Two analogous modules can be interconnected by means of a coaxial or coaxial type connection. In its simplest embodiment, the central metallization of one module is connected by solder to the central metallization of the other module, and likewise the peripheral metallizations are soldered together.
The invention provides a microwave module which as an outer face with a connection device comprising a central conductive zone and a peripheral conductive zone. Inside the volume of the module, the connection to the device is provided by means of coplanar conductors comprising firstly a central signal conductor connected to the central conductive zone and secondly lateral ground conductors connected to the peripheral conductive zone.
In an embodiment, in the vicinity of their connections to the conductive zones, the coplanar conductors are substantially perpendicular to the outer face.
In an embodiment, the peripheral conductive zone of the outer face has the shape of a closed strip or line, e.g. a shape that is substantially circular. In a variant, the peripheral conductive zone has two conductive elements that are in alignment with the conductive elements of the central zone.
In an embodiment, the width of the central conductor where it connects with the central conductive zone is equal to the width it has inside the module. It is also possible to provide for the plane central conductor to have a width where it connects with the central conductive zone which is different from the width it presents inside the module.
The distance between the central conductive zone and the peripheral conductive zone can be equal to or different from the distance between the lateral conductors of the central coplanar conductor.
In an embodiment, the conductive zones are constituted by metallization, e.g., suitable for soldering.
The invention also provides a set of two microwave modules which are connected together by means of a coaxial type member having a central portion connecting together the central conductive zones of the connection devices, and an outer conductive cylinder connecting together the peripheral conductive zones of the connection devices of the two modules.
The invention also provides an assembly of two microwave modules in which the conductive zones are constituted by metallizations suitable for soldering, the two modules being interconnected by means of points of solder extending between the central conductive zones of the two associated faces, and also between the peripheral conductive zones of the connection devices of each module.
For example, a set of solder points can be provided forming a ring for interconnecting the peripheral zones. In a variant, to connect the peripheral zones together, two solder points are provided in alignment with the solder points interconnecting the central zones.